How far does space go?

A:

Quick Answer

From Earth's surface, outer space begins at the somewhat-arbitrary Karman Line, or 100 km up, according to the Space website. From there, the observable universe stretches out without reaching any perceptible boundary.

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As of 2014, the universe is 13.8 billion years old, Space reports. Given the speed of light, this places the farthest objects that can be seen from Earth as those that sit on that boundary. The universe is expanding, so objects at the extreme range of detection have since moved to a maximum distance of 48 billion light-years. Space goes on beyond that. If the universe has a flat curvature, which it very likely does, then space could be said to extend, literally, forever.

Related Questions

The edge of space is generally recognized internationally to be at the Kármán Line, which is 62 miles from the surface of Earth. While the exact boundary of space is open to interpretation, this is the definition recognized by the Federation Aeronautique Internationale and National Aeronautics and Space Administration.

In 2009, scientists at the University of Calgary used measurements of atmospheric wind and the flow of charged particles to determine that space begins at 73 miles above the Earth's surface. However, there are competing, and sometimes conflicting, assessments of Earth's boundaries.

The nebular theory of solar system formation suggests that stars and their planets form out of cooling interstellar clouds of molecular hydrogen. As the cloud contracts, it forms a disc of dense material that forms the star. As it forms, the star throws off material that coalesces into planets.